Circuit for electric discharge device



Dec. 21 1948.

- ,V. J. FRANCIS ET AL (CIRCUIT FOR ELECTRIC DISCH Filed Aug 22, 1944 ARGE DEVICES EWM W 71%; A TTURNt') Patented Dec. 21, 1948 iJNITED STATES PATENT @FFICE CIRCUIT FOR ELECTRIC DISCHARGE DEVICES Victor J. Francis, Aylesbury, and Evan H. Nelson, Harrow Weald, England, assignors to The General Electric Company, a corporation of New York application August 22, 1944, Serial No. 550,498 in Great Britain January 1, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires January 1, 1963 Claims. (Cl. 315-284) This invention relates to combinations of gassame time the impedance of the impedor (series eous electric discharge devices with means for impedor) in series with the combination of the operating them, of the type wherein the said discharge and the parallel impedor; but this is means comprise an impedor in series with the not always necessary. The changes in the series discharge path through the device. 5 and parallel impedors should be nearly simul- It is sometimes desirable to arrange that a taneously; thus the change is preferably effected high pressure metal vapor (HPMV) device by ganged switches. If there is an interruption (lamp) should be operated alternatively either so of the circuit in series with the lamp while its as to dissipate a relatively high power (full ratimpedance is being increased, it must be so brief ing) or a relatively low power (reduced rating), that the ionisation of the vapour in the lamp which may be for example half the relatively high does not decay appreciably; the switch making power, in such a manner that the change from this change must have a very rapid action.

the reduced to the full rating can be effected in According to the invention a combination of a few seconds when the lamp is to be used. It is an I-IPMV electric discharge device with means known that this can be efiectedby providing for operating it comprises means for changing, means, e. g. a transformer of variable transduring the passage of a discharge through the formation ratio through which the lamp is fed, device, the admittance of an impedor in parallel for changing the supply voltage applied to the with the device. One of the values of the imlamp circuit; the rating is then reduced by repedance of the parallel impedor (but not of course ducing the supply voltage. However, this methof the series impedor) may be substantially inod is not always convenient. An object of the finite; none of the values of the impedance may invention is to provide an alternative method be zero. If the supply is A. C., the impedors are sometimes more convenient. both preferably chokes.

The obvious alternative is to reduce the rating on b diment f th inv tio W111 w b by increasing the p da of the p tha described by way of example with reference to is al ays i e e i the p- Bull y, the accompanying drawing in which the single based on the known voltage-cur ent c ara t figure shows schematically a circuit comprising miles of HPMV lamps and of linear impedors and our invention. The supply voltage across the confirmed by experiments, shows that this methm} terminals l, 2 is 230 at C. P. S. (cycles per 6 y r1013 ys be possible if the imped0r s second). The lamp 3 at full rating dissipates s stant a y n When t p an e is 250 watt with volts across it, the series imincreased from that characteristic of full rating pedor 4 being a, choke of 0.175 henry inductance,

to that characteristic of the reduced rating, the and there being no parauel impedor connected lamp may e in s c p ion at th uc n to the lamp. It would be impossible to make the rating as to be unstable in the sense or being lamp run stably, dissipating Watts on the unable to maintain the full operating pressure. ame upply voltage by merely increasing the If this is t e c the pressure will fall gradually impedance of the series impedor. But if the inwith the consequent loss of light. This cond ductance of the series choke is increased to 0.23

tion is likely to be obtained when the ratio of the I henry, by opening hu t witch 5 t i t an pp y Voltage t0 the running Voltage is a additional choke 6, for example, and a choke l for examp e W e the running Voltage is 59 a d of 0.68 henry inductance simultaneously placed the supply voltage 230. It should be observed in parallel with the discharge by closing switch here that t e high pp y Voltage is desirable in 8, for example, the lamp runs stably dissipating order that the lamp may start from cold; a solu- 125 w tt it 55 volts across it,

ill

tion of the difficulty y reducing the Supply VOW What we claim as new and desire to secure by a e w u d therefore su y be precluded Letters Patent of the United States is:

We have found that the d ffiC y can be i. The method of regulating the operation of avo d y increasing, While the diseharge is a high pressure metal vapor electric discharge passing through t e p, the admittance Of an m device comprising a sealed envelope containing D O (parallel impedol) in parallel With the spaced electrodes, which method comprises operdischa (It s 0 he understood that the Said ating an electric discharge at full power rating admi t y b Zero before t is increased) between said electrodes in series with a ballast The effect of the increase is to reduce the efiecimpedance, and then connecting in shunt across fi e Voltage of f e supplyt is usually desirl,. only the discharge device, while it is operating, a le, and so et m s ne s t c s a the an inductance capable of materially reducing the power dissipated in the discharge and thus maintaining the device in condition to operate substantially instantaneously at full power rating upon disconnecting the said shunting inductance.

2. The method of regulating the operation of a high pressure metal vapor electric discharge device comprising a sealed envelope containing spaced electrodes, which method comprises operating at full power rating an electric discharge between said electrodes in series with a linear ballast impedance, and then connecting in shunt across only the discharge device, While it is operating, a linear impedance capable of materially reducing the power dissipated in the discharge and thus maintaining the device in condition to operate substantially instantaneously at full power rating upon disconnecting the said shunting impedance.

3. The method of regulating the operation of a high pressure metal vapor electric discharge lamp which comprises operating the lamp at a relatively high rating of power dissipation'in series with a ballast impedance, and then connecting in shunt across only the lamp, While it is operating, an inductance capable of materially reducing the power dissipated in the lamp and thus maintaining the lamp in condition to operate substantially instantaneously at the said high rating upon disconnecting the said shunting inductance.

4. The method of regulating the operation of a high pressure metal vapor electric discharge lamp which comprises operating the lamp at a relatively high rating of power dissipation in series with a ballast impedance, and then connecting in shunt across only the lamp, while it ate the lamp at full power rating, an inductance, and means to connect said inductance in shunt across only the lamp while it is operating and to simultaneously increase the value of the series ballast impedance, said inductance being capable of materially reducing the power dissipated in the lamp with continued stable operation of the reduced power rating.

VICTOR J. FRANCIS.

EVAN H. NELSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,930,123 Ewest Oct. 10, 1933 2,043,023 Westendorp June 2, 1936 2,046,980 Van Wijk July 7, 1936 2,103,039 Pirani Dec. 21, 1937 2,170,447 Edwards Aug. 22, 1939 2,178,011 Von Wedel Oct. 31, 1939 2,278,256 Frech Mar. 31, 1942 2,339,051 Gates Jan. 11, 1944 2,339,307 Warsher Jan. 18, 194i 

